Pressure regulators are commonly used to maintain a preselected pressure within liquid systems. As disclosed in U.S. Pat. Nos. 5,076,320, 4,825,835 and 4,633,901, a typical pressure regulator usually comprises a housing which can be divided into a control chamber and a liquid chamber by a diaphragm assembly. A liquid introduction path and a liquid discharge path communicate with the liquid chamber, by which liquid can enter and exit the liquid chamber. The diaphragm assembly has a valve member to control the exit of excess liquid from the liquid chamber. A vacuum port communicates between the control chamber and a vacuum system for adjusting the valve member. However, such a pressure regulator lacks the ability of dampening wave pulses in a liquid system. Any wave pulse generated by cyclically operated injectors or pumps will remain in the liquid system and can affect the performance of the pressure regulator and other parts in the liquid system.
Dampeners are usually used in liquid systems to dampen pressure fluctuations caused either by pressure pulses in injection valves or by liquid feed pumps. As disclosed in U.S. Pat. Nos. 4,679,537 and 4,265,274, a typical dampener comprises a housing divided into a liquid chamber and a dampening chamber by a diaphragm assembly. The dampening chamber can either absorb excess pressure or compensate insufficient pressure in the liquid chamber due to pressure fluctuations. However, such a dampener lacks the necessary mechanism to maintain a predetermined pressure within the liquid system, and therefore is limited to the application where a liquid pressure is maintained by other system components.
It is desirable to provide a pressure regulator and dampener assembly, and particularly a liquid pressure regulator and dampener assembly to regulate liquid pressure while at the same time, absorbing liquid pressure pulse waves in a liquid system. The present invention provides an assembly which meets these requirements.